The present invention relates generally to wireless communications and more specifically to techniques for multiple receiver aggregation with multiple responses.
Multiple receiver aggregation (MRA) is useful in the Media Access (MAC) Layer to achieve high throughput (HT) for next generation 802.11 wireless networks. For example, an 802.11n MRA aggregate sends one large frame, a Physical Layer Protocol data unit (PPDU), containing multiple Physical Layer Service Data Units (PSDUs) to one or more receivers. Each receiver responds with an acknowledgement (ACK) or block ACK (BA) indicating the PSDUs were received. However, there are many challenges though in obtaining a reliable and feasible form of MRA. Hidden nodes, for example, can make it almost impossible for multiple receivers to respond to a MRA aggregate immediately in a distributed manner. Moreover, in a mixed network having legacy and HT nodes, a legacy node which does not recognize a HT MAC Protocol Data Unit (MPDU) can potentially contend for the wireless medium if the wireless medium is idle more than a Short Inter-Frame Space (SIFS) time between multiple acknowledgements (ACKs) or block acknowledgements (BAs), potentially causing some or all of the multiple ACKs or BAs after the SIFS to fail. Thus, a reliable and efficient method for sending MRA frames is desired.